drivers/gpu/drm/ttm/ttm_execbuf_util.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29 #include <drm/ttm/ttm_execbuf_util.h>
  30 #include <drm/ttm/ttm_bo.h>
  31
  32 static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
  33                                               struct ttm_validate_buffer *entry)
  34 {
  35         list_for_each_entry_continue_reverse(entry, list, head) {
  36                 struct ttm_buffer_object *bo = entry->bo;
  37
  38                 dma_resv_unlock(bo->base.resv);
  39         }
  40 }
  41
  42 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
  43                                 struct list_head *list)
  44 {
  45         struct ttm_validate_buffer *entry;
  46
  47         if (list_empty(list))
  48                 return;
  49
  50         list_for_each_entry(entry, list, head) {
  51                 struct ttm_buffer_object *bo = entry->bo;
  52
  53                 ttm_bo_move_to_lru_tail_unlocked(bo);
  54                 dma_resv_unlock(bo->base.resv);
  55         }
  56
  57         if (ticket)
  58                 ww_acquire_fini(ticket);
  59 }
  60 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  61
  62 /*
  63  * Reserve buffers for validation.
  64  *
  65  * If a buffer in the list is marked for CPU access, we back off and
  66  * wait for that buffer to become free for GPU access.
  67  *
  68  * If a buffer is reserved for another validation, the validator with
  69  * the highest validation sequence backs off and waits for that buffer
  70  * to become unreserved. This prevents deadlocks when validating multiple
  71  * buffers in different orders.
  72  */
  73
  74 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  75                            struct list_head *list, bool intr,
  76                            struct list_head *dups)
  77 {
  78         struct ttm_validate_buffer *entry;
  79         int ret;
  80
  81         if (list_empty(list))
  82                 return 0;
  83
  84         if (ticket)
  85                 ww_acquire_init(ticket, &reservation_ww_class);
  86
  87         list_for_each_entry(entry, list, head) {
  88                 struct ttm_buffer_object *bo = entry->bo;
  89                 unsigned int num_fences;
  90
  91                 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
  92                 if (ret == -EALREADY && dups) {
  93                         struct ttm_validate_buffer *safe = entry;
  94                         entry = list_prev_entry(entry, head);
  95                         list_del(&safe->head);
  96                         list_add(&safe->head, dups);
  97                         continue;
  98                 }
  99
 100                 num_fences = max(entry->num_shared, 1u);
 101                 if (!ret) {
 102                         ret = dma_resv_reserve_fences(bo->base.resv,
 103                                                       num_fences);
 104                         if (!ret)
 105                                 continue;
 106                 }
 107
 108                 /* uh oh, we lost out, drop every reservation and try
 109                  * to only reserve this buffer, then start over if
 110                  * this succeeds.
 111                  */
 112                 ttm_eu_backoff_reservation_reverse(list, entry);
 113
 114                 if (ret == -EDEADLK) {
 115                         ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
 116                 }
 117
 118                 if (!ret)
 119                         ret = dma_resv_reserve_fences(bo->base.resv,
 120                                                       num_fences);
 121
 122                 if (unlikely(ret != 0)) {
 123                         if (ticket) {
 124                                 ww_acquire_done(ticket);
 125                                 ww_acquire_fini(ticket);
 126                         }
 127                         return ret;
 128                 }
 129
 130                 /* move this item to the front of the list,
 131                  * forces correct iteration of the loop without keeping track
 132                  */
 133                 list_del(&entry->head);
 134                 list_add(&entry->head, list);
 135         }
 136
 137         return 0;
 138 }
 139 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 140
 141 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 142                                  struct list_head *list,
 143                                  struct dma_fence *fence)
 144 {
 145         struct ttm_validate_buffer *entry;
 146
 147         if (list_empty(list))
 148                 return;
 149
 150         list_for_each_entry(entry, list, head) {
 151                 struct ttm_buffer_object *bo = entry->bo;
 152
 153                 dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ?
 154                                    DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
 155                 ttm_bo_move_to_lru_tail_unlocked(bo);
 156                 dma_resv_unlock(bo->base.resv);
 157         }
 158         if (ticket)
 159                 ww_acquire_fini(ticket);
 160 }
 161 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);